This invention relates in general to devices for igniting a gas, and in particular to an igniter for igniting a gas being flared from a gas discharge pipe such as in oil and gas well drilling and production.
In oil and gas well drilling, a drill bit is rotated by a string of drill pipe from a drill rig. Drilling fluid, normally a liquid containing water and various chemicals known as "mud," is pumped down the drill pipe, and circulated up the annulus surrounding the drill pipe. The mud returns formation cuttings to the surface, cools the drill bit and also prevents the well from blowing out. The weight of the mud is selected so that it will exert a greater hydrostatic force than the formation pressure to prevent formation fluids from blowing the mud out of the hole.
It is not uncommon to experience gas kicks that blow a certain amount of mud from the well and result in a large gas bubble that flows to the surface. Often this is due to unexpected high pressure zones. When this occurs, the drill pipe can be sealed at the rig floor, with the gas being discharged out a flare line, which extends outward from the drill rig about 250 feet or so, if possible. Flare lines or gas discharge lines are also used in well production and drill stem testing operations, wherein the well is tested by isolating the formation from well hydrostatic pressure and allowing the formation fluid to flow upward through the drill pipe to the surface. Gas is also flared in certain production operations through vertical flares.
It is necessary to burn the gas being discharged out the flare line. This is sometimes a problem because of the poor quality of the gas being produced. Mud, acid, and other liquids will blow out the flare line along with the gas, thus tending to extinguish any flame. In the prior art technique for nonvertical lines, a bucket containing a liquid fuel or material soaked with fuel is placed and ignited near the end of the flare line to ignite any gas being produced out the flare line. The liquids being discharged often extinguish the flame of the igniting materials. Re-igniting is dangerous for operating personnel because of the proximity to the flare line when igniting the gas.
In the prior art vertical stack techniques, a fuel soaked rag or the like might be ignited and thrown upward in the vicinity of the stack. Also, burners have been placed inside stacks, but they eventually failed because of high temperatures.